Multiple heterogeneous isolates of Cryptosporidium serpentis from captive snakes are not transmissible to neonatal BALB/c mice (Mus musculus)

Oral inoculation of 9 litter-groups of 3-5-day-old suckling BALB/c mouse pups (Mus musculus) with 6.7 x 10³ to 1.2 x 10⁵ per pup of viable, Cryptosporidium serpentis oocysts from snakes resulted in no transmission. Mice showed normal development; the litter-group weight gain was not altered significantly (P > 0.05) relative to the total number of C. serpentis oocysts inoculated or to the initial group weight (P > 0.05). Histological sections of stomach, duodenum, jejunum, ileum, cecum, and colon 4 days postinoculation did not contain life-cycle stages of Cryptosporidium in any inoculated mice. Because these neonatal, C. parvum-susceptible BALB/c mice were resistant to infection it is unlikely that C. serpentis transmission to the snakes 'via infected prey' results when captive snakes are maintained on a diet of BALB/c mice.